so i am attaching a workbook where i have list of my customers in 2017 and 2018. each customer has a category. some customers stayed in the same category in both 2017 and 2018, bust some customers change categories. so for example customer cda was in category A in 2017 and switched to category E in 2018. some customers didn't change category (customer ty)

how can i track those changes. i want to find a way to be able to show how many of customers are making changes from A to E or any different categories. i want to be able to show percentages as well. something like 20% of my customers changed from A to B in 2018 and so on, and want to show new customers in 2018 (customer CDS)and customers who had a category in 2017 and no longer in 2018(customer io)

question i have is how do you read the table? so if i am looking across, does this tell me that total customers who had category A is 2017 is 4 and that 2 switched to B and 2 customers switched to E?

does this view along tell me that number of customers in 2018 who are B category are 4?

how do I read the Null?

the reason i am asking is because the spreadsheet that i have has about 1 million rows. if i do a count distinct of my customers in 2017 and select category A for example, this number doesn't match the grand total when i look at it using the calculations you created and look across for 2017. so the grand total in 2017 (using your calculations) when i look across is different than the count of distinct customers when i just simply select a category, a year and count of customers. any idea why this is happening?

so see below what i mean: the number of unique customers is showing 226,180 in this calculation

but when i do distinct count of customers for GTR category in 2017 it's showing a different number: below i am filtering on 2017 and the GTR category and doing a simple distinct count of customers. any idea what could be wrong?